Broadband Low-Beam-Coupling Dual-Beam Phased Array

ABSTRACT

Broadband slot-coupled stacked patch antenna elements are capable of continuous broadband operation between 1.71 GHz and 2.69 GHz. The broadband slot-coupled stacked patch antenna element includes a mid-band radiating patch, a high-band radiating patch, and a low-band resonator with coupling slots capable of resonating at low, mid, and high band frequencies. Additionally, a low-profile probe-fed patch element is provided for pattern enhancement of antenna arrays at high-band frequencies. This low-profile patch element features fan-shaped probes that have three degrees of tune-ability, namely a length, a width, and a spreading angle. Further aspects include 3-column and 4-column offset arrays of the broadband patch radiators and an interleaved array of the low-profile high-band patch radiators and the broadband radiating elements. A new type of azimuth beam forming network (ABFN) is also introduced for the beam forming of the 3-column and 4-column dual-beam arrays.

This application claims the benefit of U.S. Provisional Application No.61/863,203 filed on Aug. 7, 2013, entitled “broadband low-beam-couplingdual-beam phased array,” which is incorporated herein by reference as ifreproduced in its entirety.

TECHNICAL FIELD

The present invention relates generally to wireless communications, andin particular embodiments, to a broadband low-beam-coupling dual-beamphased array.

BACKGROUND

Modern day wireless cellular antennas can emit a single or multiple beamsignal. Single beam antennas emit a single beam signal pointing at thebore-sight direction of the antenna, while dual-beam antennas emit twoasymmetric beam signals pointing in two different directions in oppositeoffset angles from the mechanical bore-sight of the antennas. In a fixedcoverage cellular network, azimuth beam patterns of a dual-beam antennaare narrower than that of a single beam antenna. For example, adual-beam antenna may emit two beams having a half power beam width(HPBW) of about thirty-three degrees in the azimuth direction, while asingle beam antenna may emit one beam having a HPBW of about sixty-fivedegrees in the azimuth direction. The two narrow beams emitted by thedual-beam antenna may typically point in offset azimuth directions,e.g., plus and minus twenty degrees to minimize the beam coupling factorbetween the two beams and to provide 65 degree HPBW coverage in athree-sector network.

SUMMARY OF THE INVENTION

Technical advantages are generally achieved, by embodiments of thisdisclosure which describe a broadband low-beam-coupling dual-beam phasedarray.

In accordance with an embodiment, a broadband radiating element isprovided. In this example, the broadband radiating element includes alow-band resonator mounted above an antenna reflector, a mid-bandradiating patch mounted above the low-band resonator, and a high-bandradiating patch mounted above the mid-band radiating patch. The low-bandresonator is positioned between the mid-band radiating patch and theantenna reflector.

In accordance with another embodiment, a probe-fed patch radiatingelement is provided. In this example, the probe-fed patch radiatingelement includes a first printed circuit board (PCB) positioned below anantenna reflector, a second PCB positioned above the antenna reflector,a plurality of feed wires extending through the antenna reflector, and aradiating patch positioned above the second PCB. A plurality ofmicrostrip feed-lines are printed on the first PCB, and a plurality offan-shaped probes are printed on the second PCB. The plurality of feedwires conductively couple the microstrip feed-lines to the fan-shapedprobes, and the radiating patch is electromagnetically coupled to thefan-shaped probes.

In accordance with yet another embodiment, an antenna is provided. Inthis example, the antenna includes an antenna reflector, a plurality ofhigh-band radiating elements mounted to the antenna reflector, and aplurality of broadband radiating elements mounted to the antennareflector. The plurality of high-band radiating elements are configuredto radiate in a narrow high-band frequency, and the plurality ofbroadband radiating elements are configured to radiate in a widefrequency band that includes the narrow high-band frequency.

In accordance with yet another embodiment, yet another antenna isprovided. In this example, the antenna includes an antenna reflector,and a plurality of broadband radiating elements mounted to the antennareflector. The plurality of broadband radiating elements are arranged ina multi-column array comprising a first set of rows interleaved with asecond set of rows. Broadband radiating elements in the first set ofrows are horizontally shifted in relation to broadband elements in thesecond set of rows.

In accordance with yet another embodiment, an apparatus comprising anarray of radiating elements and an azimuth beam forming network (ABFN)structure coupled to the array of radiating elements is provided. Inthis example, the ABFN structure is configured to receive a left-handbeam and a right-hand beam, to apply three or more arbitrary amplitudeshifts to duplicates of the left-hand beam to obtain at least three ormore amplitude-shifted left-hand beams, and to apply three or morearbitrary phase shifts to duplicates of the right-hand beam to obtainthree or more phase-shifted right-hand beams. The AFBN structure isfurther configured to mix the three or more phase-shifted right-handbeams with respective ones of the three or more amplitude-shiftedleft-hand beams to obtain three or more mixed signals, and to forwardduplicates of the three or more mixed signals to respective radiatingelements in odd rows of the array of radiating elements. The AFBMstructure is further configured to adjust a pre-tilt angle to duplicatesof the three or more mixed signals to obtain three or more pre-tiltangle adjusted signals, and to forward the three or more pre-tilt angleadjusted signals to respective radiating elements in even rows of thearray of radiating elements.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure, and theadvantages thereof, reference is now made to the following descriptionstaken in conjunction with the accompanying drawings, in which:

FIG. 1 illustrates a diagram of a conventional dual-beam antenna array;

FIG. 2 illustrates a diagram of a conventional low-band radiatingelement;

FIG. 3 illustrates a diagram of a conventional high-band radiatingelement;

FIGS. 4A-4D illustrate diagrams of an embodiment broadband slot-coupledstacked patch element;

FIG. 5 illustrates a graph of radiation patterns produced by anembodiment broadband slot-coupled stacked patch element;

FIG. 6 illustrates a graph of voltage standing wave ratios (VSWRs)achieved by an embodiment broadband radiating element;

FIG. 7 illustrates a graph of port isolations achieved by an embodimentbroadband radiating element;

FIGS. 8A-8D illustrate diagrams of an embodiment low-profile probe-fedradiating element;

FIG. 9 illustrates a graph of radiation patterns produced by anembodiment low-profile probe-fed radiating element;

FIG. 10 illustrates a graph of voltage standing wave ratios (VSWRs)achieved by an embodiment low-profile probe-fed radiating element;

FIG. 11 illustrates a graph of port isolations achieved by an embodimentlow-profile probe-fed radiating element;

FIGS. 12A-12B illustrate diagrams of an embodiment broadband antennaarray architecture;

FIGS. 13A-13B illustrate diagrams of additional embodiment antenna arrayarchitectures;

FIG. 14 illustrates a graph of an azimuth radiation pattern achieved byan embodiment broadband antenna array;

FIG. 15 illustrate diagrams of an embodiment horizontal-paring arbitraryfunction azimuth beam forming network (ABFN);

FIGS. 16A-16B illustrate diagrams of embodiment of vertical-pairingarbitrary function azimuth beam forming networks (ABFNs);

FIG. 17 illustrates a diagram of an embodiment microstrip layout of an3-column azimuth beam forming network (ABFN);

FIG. 18 illustrates a signal flow diagram of the azimuth beam formingnetwork (ABFN); and

FIG. 19 illustrates a block diagram of an embodiment manufacturingdevice.

Corresponding numerals and symbols in the different figures generallyrefer to corresponding parts unless otherwise indicated. The figures aredrawn to clearly illustrate the relevant aspects of the embodiments andare not necessarily drawn to scale.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The making and using of embodiments of this disclosure are discussed indetail below. It should be appreciated, however, that the conceptsdisclosed herein can be embodied in a wide variety of specific contexts,and that the specific embodiments discussed herein are merelyillustrative and do not serve to limit the scope of the claims. Further,it should be understood that various changes, substitutions andalterations can be made herein without departing from the spirit andscope of this disclosure as defined by the appended claims.

Base station antennas often use arrays of antenna elements in order toachieve enhanced spatial selectivity (e.g., through beamforming) as wellas higher spectral efficiency. Conventional dual-beam antenna arrays maybe configured to perform transmissions over frequencies within aUniversal Mobile Telecommunications System (UMTS) band (e.g., between1.71 GHz and 2.17 GHz) and frequencies within a long term evolution(LTE) frequency band (e.g., between 2.49 GHz and 2.69 GHz), but not overfrequencies encompassing both the UMTS and LTE bands (e.g., between 1710MHz and 2690 MHz). Accordingly, mechanisms and techniques for providingantenna arrays capable of continuous broadband operation (e.g., between1.7 GHz and 2.69 GHz) are desired.

Aspects of this disclosure provide broadband slot-coupled stacked patchantenna elements that are capable of continuous broadband operationbetween 1.71 GHz and 2.69 GHz. This broadband slot-coupled stacked patchantenna element includes a mid-band radiating patch, a high-bandradiating patch, and a low-band resonator with coupling slots capable ofresonating at low, mid, and high band frequencies. Aspects of thisdisclosure also provide a low-profile probe-fed patch element forpattern enhancement of the array at high-band frequencies. Thislow-profile patch element features fan-shaped probes that have threedegrees of tune-ability, namely a length, a width, and a spreadingangle. Additional aspects of this disclosure provide 3-column and4-column offset arrays of the broadband patch radiators and aninterleaved array of the low-profile high-band patch radiators andbroadband radiating elements.

FIG. 1 illustrates a conventional dual-band antenna array 100 comprisinga radome 110, a plurality of low-band radiating elements 120, and aplurality of high-band radiating elements 130. As shown, the low-bandradiating elements 120 and the high-band radiating elements are arrangedin a single column. Notably, the low-band radiating elements 120 aretypically collocated and configured to radiate in a different frequencyband than the high-band radiating elements 130. Also, high-bandradiators are typically superimposed with the low-band radiators atlocations where signals of both bands must be radiated at co-locations.

FIG. 2 illustrates a conventional low-band radiating element 200 mountedto an antenna reflector 210. The low band radiating element 200comprises a back cavity 222, a printed circuit board (PCB) 224, and alow-band radiating element 226. The back cavity 222 houses activeantenna components, and the PCB 224 includes interconnections forallowing the active antenna components to drive the low-band radiatingelement 226. FIG. 3 illustrates a conventional high-band radiatingelement 300 having a structure that is similar to the conventionallow-band radiating element 200. The conventional high-band radiatingelement 300 is mounted to an antenna reflector 310, and comprises a backcavity 332, a PCB 334, and a low-band radiating element 336 configuredin a similar way to like components of the conventional low-bandradiating element 200. Notably, the high-band radiating element 300 isconfigured to operate in a different frequency band than the low-bandradiating element 200.

Aspects of this disclosure describe a broadband slot-coupled stackedpatch radiating element that is configured to provide continuousbroadband operation between 1.71 GHz and 2.69 GHz, providing a totalsignal bandwidth of over 45% with VSWR of 1.5:1. FIG. 4A illustrates anembodiment broadband slot-coupled stacked patch radiating element 400mounted to an antenna reflector 410. As shown, the radiating element 400comprises a low-band resonator 420, a low-band radiating patch 430, ahigh-band radiating patch 440, and a central feed 450. The low-bandresonator 420 is positioned above the antenna reflector 410, andincludes bent edges that serve to extend the signals radiated by theradiating patches 430, 440 to a low-frequency bandwidth. The mid-bandradiating patch 430 is positioned above the low-band resonator 420, andthe high-band radiating patch 440 is positioned above the mid-bandradiating patch 430. Non-conductive spacers 425 are positioned betweenthe low-band resonator 420 and the low-band radiating patch 430, andnon-conductive spacers 435 are positioned between the high-bandradiating patch 440 and the low-band radiating patch 440. Notably, thelow-band resonator 420 includes cross-slots 422 and an opening throughwhich the central feed 450 extends. The central feed 450 includesmicrostrip feedlines 452 which supply power to the radiating patches430, 440. More specifically, the central feed 450 couples RF power fromthe PCB at the bottom of the reflector to the cross-slots, where powerare electromagnetically coupled to both the mid-band radiating patch 430and the high-band radiating patch 440 without being in physical contactwith the radiating patches 430, 440. FIG. 4B illustrates a side view ofthe radiating element 400, while FIG. 4C illustrates a top view of theradiating element 400. The central feed 450 may include four center pinsencased by a cylindrical tube, where the four center pins form shortcoaxes that carry RF signals from the PCB through the cross-slots to theradiating patches 430, 440. FIG. 4D shows typical excitation arrangementfor the broadband slot-coupled stacked patch for dual linearpolarization. The two cross slots are fed by four feed ports at thebottom PCB. For a linear positive 45° polarization operation, the twoports P1 and P2 are excited in equal amplitude with opposite phase (0°and 180°), while the other two ports N1 and N2 are excited in thesimilar fashion for linear negative 45° polarization operation. Thesetwo linear polarizations can be operating simultaneously.

FIG. 5 illustrates a graph of radiation patterns produced by theembodiment broadband radiating element 400. As shown, the embodimentbroadband radiating element produces uniform radiation patterns acrossthe various sample frequencies. FIG. 6 illustrates a graph of voltagestanding wave ratios (VSWRs) achieved by the embodiment broadbandradiating element 400. As shown, the embodiment broadband radiatingelement maintains a relatively low VSWR (e.g., below about 1.4) for muchof the frequency spectrum ranging from about 1.7 GHz to 2.7 GHz. FIG. 7illustrates a graph of port isolations achieved by the embodimentbroadband radiating element 400. As shown, the embodiment broadbandradiating element 400 maintains port isolation between the twopolarization modes of less than 30 dB over much of the frequencyspectrum ranging from about 1.7 GHz to 2.7 GHz.

FIG. 8A illustrates an embodiment probe-fed patch element 800 mounted toan antenna reflector 810. As shown, the proposed probe-fed patch element800 comprises a PCB 805, a plurality of feed wires 820, a PCB 830, and aradiating patch 840. The PCB 830 includes a plurality of fan probes 832,which are conductively coupled to microstrip feed lines in the PCB 805by the feed wires 820. Signals from the fan probes 832 are thenelectromagnetically coupled to the radiating patch 840. In someembodiments, the radiating patch 840 is suspended above the surface ofthe PCB 830 by non-conductive spacers 835 such that the radiating patch840 and the fan probes 832 are not in direct/physical contact. FIG. 8Billustrates a side view of the narrowband radiating element 800, whileFIG. 8C illustrates a top view of the narrowband radiating element 800.As shown in FIG. 8C, the fan probes 832 extend inwards, towards thecenter of the PCB 830. Further, a width of the fan probes 832 increasesas the fan probes 832 extend inwardly, thereby giving the fan probes 832a fan-like shape. Notably, the fan-fed probes 832 offer enhancedtune-ability, as their dimensions (e.g., length (L), width (W), andspreading angle (θ)) can be manipulated to achieve different bandwidthcharacteristics. FIG. 8D shows typical excitation arrangement for theprobe-fed patch for dual linear polarization. Each of the fan-shapedprobes is fed by an independent port at the bottom PCB. For a linearpositive 45° polarization operation, the two ports P1 and P2 are excitedin equal amplitude with opposite phase (0° and 180°), while the othertwo ports N1 and N2 are excited in the similar fashion for linearnegative 45° polarization operation. These two linear polarizations canbe operating simultaneously. The probe-fed element 800 have a lowerprofile than embodiment broadband radiating elements provided by thisdisclosure. This difference in profile thickness reduces inter-bandinterference when both the high-band radiating elements 800 andembodiment broadband radiating elements are included in an antenna arrayconfiguration.

FIG. 9 illustrates a graph of radiation patterns produce by theembodiment narrowband radiating element 800. As shown, the embodimentnarrowband radiating element 800 produces broad half power beamwidth(HPBW) across the various sample frequencies. Beam shapes having broadHPBWs may be desirable at high-band radiating frequencies, as they maytend to compensate for the narrower high band patterns produced bybroadband arrays and therefore improve the overall coverage performanceat high-band frequencies.

FIG. 10 illustrates a graph of VSWRs achieved by the embodimentprobe-fed element 800. As shown, the embodiment probe-fed element 800maintains a relatively low VSWR (e.g., below about 1.4) for much of thefrequency spectrum ranging from about 2.1 GHz to 2.9 GHz. FIG. 11illustrates a graph of port isolation achieved by an embodimentnarrowband radiating element. As shown, the embodiment narrowbandradiating element maintains a port isolation between the twopolarization modes of less than 30 dB over much of the frequencyspectrum ranging from about 2.2 GHz to 2.8 GHz.

FIG. 12A illustrates an embodiment broadband antenna array architecture1200 comprising rows of broadband radiating elements 1210, 1220interleaved with rows of high-band elements 1230, 1240. In someembodiments, the broadband radiating elements 1210, 1220 may beconfigured similarly to the embodiment broadband radiating element 400described above, while the high-band elements 1230, 1240 may beconfigured similarly to the embodiment probe-fed element 800 describedabove.

As show in FIG. 12B, the odd rows of high-band elements 1230 arehorizontally shifted in relation to the even rows of high-band elements1240, while the odd rows of broadband elements 1210 are horizontallyshifted in relation to the even rows of broadband elements 1220. Withproper amount, this horizontal shift (HS) allows reduction in radiationside-lobes in the azimuth plane without loss of directivity.Additionally, the high-band elements are also shifted in the horizontaldirection with respect to the broadband elements to provide optimumhorizontal patterns for the high-band signals. In cases where cost isthe primary concern, the offset array can be constructed using only thebroadband radiators without interleaving the high-band radiators. FIG.13A illustrates an embodiment 4-column broadband offset arrayarchitecture 1301. FIG. 13B illustrates an embodiment 3-column broadbandoffset array architecture 1302. The offset architectures 1301 and 1302may use broadband radiators.

In some embodiments, the embodiment broadband antenna arrays may achieveimproved operation by including an element spacing that is approximatelyone-half wavelength in the azimuth direction and/or slightly overone-half wavelength in the elevation direction. For improved beampatterns across the a frequency band from 1710 MHz to 2690 MHz, anazimuth spacing of the broadband elements may be selected to optimizethe low-band performance, while the azimuth spacing of the narrowbandradiating elements is selected to optimize the high-band performance.The broadband radiators may be distributed in an offset four-columnconfiguration for improved aperture efficiency. The lower-profilenarrowband radiating elements can be inserted between the broadbandarrays. In some embodiments, alternating rows of narrowband/broadbandradiating elements are offset in the azimuth direction to achieve lowside-lobe performance for high and low frequency bands. In thisconfiguration, the azimuth beams are first formed for each sub-group ofarray consisting of two or more rows of the array, using tailor-made 4×2or 3×2 azimuth beam forming network (ABFN). A multi-port variable phaseshifters is then used to feed these ABFNs to complete formation of the2-dimensional array.

FIG. 14 illustrates an azimuth radiation pattern achieved by theembodiment broadband antenna array architecture 1200. In a dual-linearlypolarized array, for each frequency of operation, there are fourindependent asymmetric beams: Left Positive 45° (LP), Right Positive 45°(RP), Left Negative 45° (LN) and Right Negative 45° (RN) beams. Toencompass a typical 65° cell coverage, each of the dual-beam arrayprovides azimuth beam patterns with an azimuth HPBW of approximately33°. This way, the combined HPBW of the two beams can provideapproximately the same coverage of a standard 65° beam. Beam shapes ofthe radiation patterns are carefully designed such that each componentbeam (left and right) are orthogonal to each other with very low beamcoupling factor. The design parameters may be designed in accordancewith the following formula: Min (β_(RL))=min (k*∫E_(R)(θ,Φ)·E_(L)(θ,Φ)dΩ), where k is normalization constant, E_(R)(θ,Φ) represents theradiation pattern of the right beam, and E_(L)(θ,Φ) represents theradiation pattern of the left beam. Low beam coupling factor, β_(RL),implies highly orthogonal component beams, which is critical for theoptimum network performance. Other typical features of these patternsinclude high roll-off rate at points where the two component beamsintersect, low azimuth side lobes, beam cross-over −7 dB to −13 dBbetween patterns, good front to back ratio of typically over 30 dB inthe back of the antenna. Through the virtue of orthogonality of the BFNand spectrum isolation between the two bands, the four asymmetric beamsproduced by the broadband BSA can be reduced to extremely low values.Therefore, this architecture results in significantly improved networkperformances without having the penalty of increasing the overall sizeof a base-station antenna.

FIG. 15 illustrates an embodiment azimuth beam forming network (ABFNs)1500 for a 4-column array. FIG. 16A illustrates an ABFN 1601 for3-column array. FIG. 16B illustrates an ABFN 1602 for 4-column array.These ABFN configurations offer higher degrees of freedom on beamshaping and can achieve beam orthogonality as a result of flexibility onexcitation weighting function. Compared to a Butler matrix and 3-columnABFN, the embodiment ABFNs 1500, 1601, 1602 offer more degree-of freedomin achieving pattern side-lobe levels and roll-off rate of beam shape inthe azimuth direction. Table I and II give a typical azimuth excitationweight functions for the low-band (LB) and high-band (HB) beams, wherethe β represents the required azimuth phase offset angle between rows.For the Low-band operations, only the full-band elements are excited.For high-band operations, both the full-band and high-band radiators areexcited according to the Table II.

TABLE 1 Low-band Az excitation weight function Array ABFN Left Beam (L)Right Beam (R) Element Port Amp (W) Phase (deg) Amp (W) Phase (deg) FB11 (A₁, Φ₁) 0.5 −180-β 0.5 0 FB 12 (A₂, Φ₂) 1  −85-β 1 −85 FB 13 (A₃,Φ₃) 0.5   0-β 0.5 −180 FB 14 (A₅, Φ₅) 0.08 +110-β 0 NA FB 21 (A₄, Φ₄) 0NA 0.08 +110-β FB 22 (A₁, Φ₁) 0.5 −180 0.5   0-β FB 23 (A₂, Φ₂) 1 −85 1 −85-β FB 24 (A₃, Φ₃) 0.5 0 0.5 −180-β

TABLE 2 High-band Az excitation weight function Array ABFN Left Beam (L)Right Beam (R) Element Port Amp (W) Phase (deg) Amp (W) Phase (deg) FB11 (A₁, Φ₁) 0.5 −180-β 0.5 0 FB 12 (A₂, Φ₂) 1  −85-β 1 −85 FB 13 (A₃,Φ₃) 0.5   0-β 0.5 −180 FB 14 (A₅, Φ₅) 0.08 +110-β 0 NA FB 21 (A₄, Φ₄) 0NA 0.08 +110-β FB 22 (A₁, Φ₁) 0.5 −180 0.5   0-β FB 23 (A₂, Φ₂) 1 −85 1 −85-β FB 24 (A₃, Φ₃) 0.5 0 0.5 −180-β HB 1 (A₁, Φ₁) 0.5 −180 0.5   0-βHB 2 (A₂, Φ₂) 1 −85 1  −85-β HB 3 (A₃, Φ₃) 0.5 0 0.5 −180-β HB 4 (A₁,Φ₁) 0.5 −180-β 0.5 0 HB 5 (A₂, Φ₂) 1  −85-β 1 −85 HB 6 (A₃, Φ₃) 0.5  0-β 0.5 −180

FIG. 17 illustrates an embodiment microstrip layout of an ABFN 1700. Asshown, the ABFN 1700 includes a plurality of resistors 1705, as well asa five antenna ports (AP1, AP2, AP3, AP4, and AP5), a left beam port(L-Beam), and a right beam port (R-Beam). FIG. 18 illustrates anembodiment schematic and signal flow of the ABFN.

FIG. 19 illustrates a block diagram of an embodiment manufacturingdevice 1900, which may be used to perform one or more aspects of thisdisclosure. The manufacturing device 1900 includes a processor 1904, amemory 1906, and a plurality of interfaces 1910-1912, which may (or maynot) be arranged as shown in FIG. 19. The processor 1904 may be anycomponent capable of performing computations and/or other processingrelated tasks, and the memory 1906 may be any component capable ofstoring programming and/or instructions for the processor 1904. Theinterfaces 1910-1912 may be any component or collection of componentsthat allows the device 1900 to communicate control instructions to otherdevices, as may be common in a factory setting.

Although the description has been described in detail, it should beunderstood that various changes, substitutions and alterations can bemade without departing from the spirit and scope of this disclosure asdefined by the appended claims. Moreover, the scope of the disclosure isnot intended to be limited to the particular embodiments describedherein, as one of ordinary skill in the art will readily appreciate fromthis disclosure that processes, machines, manufacture, compositions ofmatter, means, methods, or steps, presently existing or later to bedeveloped, may perform substantially the same function or achievesubstantially the same result as the corresponding embodiments describedherein. Accordingly, the appended claims are intended to include withintheir scope such processes, machines, manufacture, compositions ofmatter, means, methods, or steps.

What is claimed:
 1. A broadband radiating element comprising: a low-bandresonator mounted above an antenna reflector; a mid-band radiating patchmounted above the low-band resonator, wherein the low-band resonator ispositioned between the mid-band radiating patch and the antennareflector; and a high-band radiating patch mounted above the mid-bandradiating patch.
 2. The broadband radiating element of claim 1, whereinthe low-band radiating patch is configured to radiate in a low frequencyband, wherein the high-band radiating patch is configured to radiate ina high frequency band, and wherein the mid-band radiating patch isconfigured to resonate at inter-band frequencies between the lowfrequency band and the high frequency band.
 3. The broadband radiatingelement of claim 2, wherein the low frequency band comprises a UniversalMobile Telecommunications System (UMTS) band that includes radiofrequencies between 1.71 gigahertz (GHz) and 2.17 GHz, wherein the highfrequency band comprises a long term evolution (LTE) band that includesradio frequencies between 2.49 GHz and 2.69 GHz, and wherein theinter-band frequencies include frequencies between 2.17 GHz and 2.49GHz.
 4. The broadband radiating element of claim 1, wherein thebroadband radiating element excludes a back-cavity.
 5. The broadbandradiating element of claim 4, wherein all components of the broadbandradiating element are positioned above the antenna reflector.
 6. Thebroadband radiating element of claim 1, wherein the low-band resonatorcomprises a coupling cross-slots.
 7. The broadband radiating element ofclaim 6, further comprising: a printed circuit board (PCB) positionedbelow the low-band resonator, the PCB comprising microstrip feed-linesand crossed coupling slots; and a central feed assembly extendingthrough an opening in the low-band resonator, the central feed assemblyincluding 4 feed pins in a cylindrical RF shield, wherein the feed pinsdirectly couple RF power to the radiating patches through the crossedslots in the low-band resonator from the microstrip feed-lines on thePCB.
 8. The broadband radiating element of claim 7, wherein the feedpins and the mid-band radiating patch are not in direct physicalcontact.
 9. The broadband radiating element of claim 7, wherein the feedpins electromagnetically couple the high-band radiating patch to themicrostrip feed-lines on the PCB.
 10. The broadband radiating element ofclaim 7, wherein the feed pins electromagnetically couple the high-bandradiating patch to the mid-band radiating patch.
 11. A probe-fed patchradiating element comprising: a first printed circuit board (PCB)positioned below an antenna reflector, wherein a plurality of microstripfeed-lines are printed on the first PCB; a second PCB positioned abovethe antenna reflector, wherein a plurality of fan-shaped probes areprinted on the second PCB; a plurality of feed wires extending throughthe antenna reflector, the plurality of feed wires conductively couplingthe microstrip feed-lines to the fan-shaped probes; and a radiatingpatch positioned above the second PCB, wherein the radiating patch iselectromagnetically coupled to the fan-shaped probes.
 12. The probe-fedpatch radiating element of claim 11, wherein the plurality of fan-shapedprobes are not in direct physical contact with the radiating patch. 13.The probe-fed patch radiating element of claim 11, wherein thefan-shaped probes have a fixed length, and wherein a width of thefan-shaped probes increases across the fixed length.
 14. The probe-fedpatch radiating element of claim 11, wherein the fan-shaped probesextend inwardly towards a center of the second PCB, and wherein a widthof the fan-shaped probe gradually increases as the fan-shaped probeextends inwardly towards the center of the second PCB.
 15. An antennacomprising: an antenna reflector; a plurality of high-band radiatingelements mounted to the antenna reflector, wherein the plurality ofhigh-band radiating elements are configured to radiate in a narrowhigh-band frequency; and a plurality of broadband radiating elementsmounted to the antenna reflector, wherein the plurality of broadbandradiating elements are configured to radiate in a wide frequency bandthat includes the narrow high-band frequency.
 16. The antenna of claim15, wherein the broadband radiating elements are arranged in a first setof rows, and wherein the high-band radiating elements are arranged in asecond set of rows, and wherein the first set of rows are inter-leavedwith the second set of rows.
 17. The antenna of claim 16, wherein thefirst set of rows is horizontally shifted in relation to the second setof rows.
 18. The antenna of claim 16, wherein odd rows in the first setof rows are offset by a first azimuth offset in relation to even rows inthe first set of rows.
 19. The antenna of claim 16, wherein each row inthe first set of rows includes three or more consecutive broadbandradiating elements, and wherein the first three consecutive broadbandradiating elements in odd rows of the first set of rows are paired withrespective ones of the last three consecutive broadband radiatingelements in a following even row of the first set of rows to form threepairs of broadband radiating elements for each tuple of odd and evenrows in the first set of rows.
 20. The antenna of claim 19, wherein thefourth consecutive broadband radiating element in the odd rows and thefirst consecutive broadband radiating element in the even rows areunpaired.
 21. The antenna of claim 19, wherein each row in the secondset of rows includes three or more consecutive high-band radiatingelements, and wherein each consecutive high-band radiating element inodd rows of the second set of rows are paired with a correspondingconsecutive narrowband radiating element in a following even row of thesecond set of rows to form three pairs of narrowband radiating elementsfor each tuple of odd and even rows in the second set of rows.
 22. Anantenna comprising: an antenna reflector; and a plurality of broadbandradiating elements mounted to the antenna reflector, wherein theplurality of broadband radiating elements are arranged in a multi-columnarray comprising a first set of rows interleaved with a second set ofrows, wherein broadband radiating elements in the first set of rows arehorizontally shifted in relation to broadband elements in the second setof rows.
 23. The antenna of claim 22, wherein the multi-column arrayconsists of three columns of broadband radiating elements.
 24. Theantenna of claim 22, wherein the multi-column array consists of fourcolumns of broadband radiating elements.
 25. An apparatus comprising: anarray of radiating elements; and an azimuth beam forming network (ABFN)structure coupled to the array of radiating elements, the ABFN structureconfigured to receive a left-hand beam and a right-hand beam, to applythree or more arbitrary amplitude shifts to duplicates of the left-handbeam to obtain at least three or more amplitude-shifted left-hand beams,to apply three or more arbitrary phase shifts to duplicates of theright-hand beam to obtain three or more phase-shifted right-hand beams,to mix the three or more phase-shifted right-hand beams with respectiveones of the three or more amplitude-shifted left-hand beams to obtainthree or more mixed signals, to forward duplicates of the three or moremixed signals to respective radiating elements in odd rows of the arrayof radiating elements, to adjust a pre-tilt angle to duplicates of thethree or more mixed signals to obtain three or more pre-tilt angleadjusted signals, and to forward the three or more pre-tilt angleadjusted signals to respective radiating elements in even rows of thearray of radiating elements
 26. The apparatus of claim 25, wherein theABFN structure comprises a four column horizontal-paring arbitraryfunction ABFN.
 27. The apparatus of claim 25, wherein the ABFN structurecomprises a four column vertical-paring arbitrary function ABFN.
 28. Theapparatus of claim 25, wherein the ABFN structure comprises a threecolumn vertical-paring arbitrary function ABFN.